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  1. import java.util.*;
  2. class Permute{
  3.     static List<List<Integer>> permute(java.util.List<Integer> arr, int k){
  4.         List<List<Integer>> arrs = new ArrayList<>();
  5.         for(int i = k; i < arr.size(); i++){
  6.             java.util.Collections.swap(arr, i, k);
  7.             arrs.addAll(permute(arr, k+1));
  8.             java.util.Collections.swap(arr, k, i);
  9.         }
  10.         if (k == arr.size() -1){
  11.             arrs.add(new ArrayList<>(arr));
  12.         }
  13.         return arrs;
  14.     }
  15.  
  16.     public static void main(String[] args){
  17.         List<Integer> arr = new ArrayList<>(Arrays.asList(1,2,3));
  18.         System.out.println(Permute.permute(arr,0));
  19.     }
  20. }
Success #stdin #stdout 0.08s 51060KB
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Standard input is empty
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[[1, 2, 3], [1, 3, 2], [2, 1, 3], [2, 3, 1], [3, 2, 1], [3, 1, 2]]
https://ideone.com/72YB1O
language:
Java (12.0.1)
created:
4 years ago
visibility:
public

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